Self-regulating dosing dispenser

ABSTRACT

A toilet bowl cleaner dispenser which automatically increases or decreases its liquid volume output respectively in response to an increase or decrease in the concentration of cleaning material dissolved in a liquid solution in a dispenser reservoir, and a method of manufacture thereof. The dispenser, which may be fixed in a toilet tank at a designated position relative to the quiescent water level in the tank, includes an enclosure having an internal cavity containing a solid block of water soluble cleaning agent, the cavity being sealed except for an upper air vent and a lower water inflow and solution outflow opening. The air vent communicates with the exterior of the dispenser through an air inflow and outflow passage having an air opening at a vertical level between the upper air vent and the lower opening. The lower opening communicates with the exterior of the dispenser through a passage having a liquid opening at a vertical level between the air opening and the lower opening. With this structure, the desired volume of solution dispensed at each flush is obtained as a result of changes in the specific gravity of the solution reflecting changes in concentration of the cleaning material therein and causing a corresponding change in the level of the solution in the dispenser. In accordance with one method and structure of the invention, the dispenser is formed from a flexible rectangular sheet having holes prepunched therein and which is formed and sealed using heating techniques.

BACKGROUND OF THE INVENTION

1. Field of the Invention

This invention relates to an automatic toilet bowl cleaner dispenser,and more particularly to a low cost automatic toilet bowl cleaning agentdispenser which self-regulates its cleaning agent output with referenceto the concentration strength of a cleaning agent solution containedinside the dispenser, and to a method of manufacture thereof.

2. Prior Art

Current automatic toilet bowl cleaner dispensers are basically flexible,or rigid, containers containing a concentrated, solid cleaning agentmaterial. Such dispensers are mounted to the toilet tank, submerged tosome point beneath the tank water line. With some such dispensers a dosevolume of tank water is allowed to enter the container between flushcycles, absorb some of the solid cleaning agent, and is then emittedinto the tank (and ultimately into the bowl) during the next flush.

Examples of solid cleaning agents popular for this type of dispenser areconcentrated chlorine materials such as calcium hypochlorite or one ofthe chlorinated isocyanurates, and also various surfactant/blue dyemixtures. U.S. Pat. No. 4,200,606 (Kitko) discloses examples of suchsolid cleaning agents.

Regardless of the cleaning agent used, there is an optimum concentrationlevel for the cleaning agent to the toilet bowl water. Effectivecleaning action does not occur below this optimum level, and cleaningmaterial is simplY wasted when used above this optimum level.

Producers of current automatic toilet bowl cleaning agent dispensersrecognize this fact, and have attempted to regulate cleaner output byconstructing dispensers to emit a uniform volume of the concentratedwater/cleaning agent solution contained inside the unit with each flush.Examples of such prior dispensers of the rigid body type are disclosedin U.S. Pat. Nos. 3,121,236 (Yadro), 3,618,143 (Hill), and 4,186,856(Dirsking). Similar dispensers of the flexible body type are disclosedin U.S. Pat. Nos. 2,807,807 (Harper), 3,545,014 (Davis), and 3,869,069(Levey).

However, a dispenser designed to emit a uniform amount of liquid witheach flush of the toilet does not provide an optimum, or even uniform,output of cleaning agent with each flush. The concentration of solidcleaning agent dissolved into the water solution inside the dispenser atany given time is dramatically dependent upon the time the cleaningagent has been in contact with the water, how often and how much freshwater is added to the dispenser with each flush of the toilet, and thespeed at which the cleaning agent can reach its maximum saturation pointin the water under the temperature conditions present.

Current toilet bowl cleaning agent dispenser structures cannot addressthese factors. As a result, under the varying conditions found in use,their actual cleaning agent output levels are too high or too low asoften as they are proper even though their liquid volume output isuniform. As a result, the dispenser user pays for too little cleaningpart of the time, efficient cleaning part of the time, and too muchcleaning part of the time.

This effect may be readily seen by examining the operation of a uniformliquid output dispenser containing a solid chlorine cleaning agent suchas calcium hypochlorite. Calcium hypochlorite releases chlorine(hypochlorite ions) into the cleaning solution to produce an oxidizingaction which chemically breaks down stains and soils on the toilet bowlsurface. The optimum cleaning level of chlorine in the toilet bowl wateris 2 to 7 parts per million for all chlorine cleaning agents. A typicalconventional uniform liquid output cleaning agent having a dispenserdesigned for 30 days use (350 flushes) has a dispenser reservoir for 100ml of water and a 11/2 oz. block of calcium hypochlorite, with theliquid output level set for a uniform 10 ml with each flush of thetoilet.

The nonuniformity of cleaning agent dispensing over the life of such adispenser is evident from a consideration of FIG. 1 which effectivelyshows the saturation time curve for calcium hypochlorite in 100 ml ofwater. At 70° F., approximately 56 hours are required for the solutionto reach a point where the molar fraction of chlorine (hypochlorite) tothe water is as high as possible (a point where the water will notabsorb additional chlorine). At this saturation point, 10 ml of thesolution emitted into the 41/2 gallons of water in a standard toilettank will produce a 70 ppm chlorine level as shown in FIG. 1.

With a typical use of the toilet of 12 flushes per day, the minimumeffective concentration of 2 ppm chlorine would be reached within twohours of initial placement of the dispenser in a toilet tank. However,with this use the concentration would reach about 40 ppm chlorine andthen gradually diminish to zero as the chlorine is used up. This resultsin gross overuse of the chlorine during a substantial period andinsufficient use or waste of the material at the end of the use period.If the dose is reduced to reduce the maximum concentration, insufficientconcentrations will be obtained for a longer period initially and at theend of the use period.

Other conventional toilet bowl cleaning agent dispensers empty theirentire volumes of solution into the tank each time the toilet isflushed. Such dispensers therefore restart the saturation time curveafter each flush. Thus, any time the dispenser sits for several hours ordays the chlorine output for the first flush is equivalent to thatrequired for 20 or 30 flushes, and if two or more flushes are madeduring a short interval (e.g. 1/2 hour) those flushes following thefirst flush would produce far below the minimum effective 2 ppm chlorinein the toilet.

SUMMARY OF THE INVENTION

It is, therefore, an object of the present invention to provide a toiletbowl cleaning agent dispenser which dispenses an approximately uniformquantity of cleaning agent (as opposed to a uniform volume of liquid) tothe toilet each time the toilet is flushed until substantially all ofthe cleaning agent is used up, and with greater independence of thefrequency and timing of flushes than prior dispensers.

It is another object of the invention to provide such a dispenser whichmay be inexpensively produced.

It is still another object of the invention to provide an inexpensivemethod of automated manufacture of such a dispenser.

In accordance with the invention and in order to meet the above objectsthereof, there is provided a toilet bowl cleaning agent dispenser whichautomatically increases or decreases its liquid volume outputrespectively in response to an increase or decrease in the concentrationof cleaning agent dissolved in the liquid solution in the dispenserreservoir. This feature allows the output level of cleaning agent uponeach flush of the toilet to be maintained relatively constant throughthe product life, regardless of the pattern or variation of use.

In accordance with the invention, the dispenser, which may be fixed in atoilet tank at a designated position relative to the quiescent waterlevel in the tank, includes an enclosure having an internal cavitycontaining a solid block of water soluble cleaning agent, the cavitybeing sealed except for an upper air vent and a lower water inflow andsolution outflow opening. The upper air vent communicates with theexterior of the dispenser through an air flow conduit having an airopening at a vertical level between the upper air vent and the loweropening. The lower opening communicates with the exterior of thedispenser through a liquid flow conduit having a liquid opening at avertical level between the air opening and the lower opening.

By placing the dispenser in the tank with the quiescent water levelabove the air opening, water flows into the cavity through the liquidflow conduit and air is pushed out through the air flow conduit untilthe water in the cavity reaches the level of the air opening where itstops since the water in the cavity at this level and the air pressurethereabove and in the air flow conduit will then be substantially equalto the water pressure in the tank at the level of the air opening. Thewater in the cavity immediately begins to dissolve some of the solidcleaning agent in the cavity.

When the toilet is flushed, and the water level in the tank drops fromabove the air opening to below the liquid opening, the solution of waterand cleaning agent flows from the cavity into the tank through theliquid flow conduit until the level of solution in the cavity drops tothe level of the bottom of the liquid opening. The level of solutionwill again rise when the level of water in the tank again rises abovethe air opening at the end of the flush cycle.

Water in the cavity continues to dissolve more of the solid cleaningagent during quiescent and flushing periods so long as this water is notsaturated with the cleaning agent. The cleaning agent, such as calciumhypochlorite, as it dissolves typically increases the specific gravityof the solution in proportion to the increased concentration of thecleaning agent in the solution. As the specific gravity of the solutionincreases, relatively more tank water head pressure is required to raisethe solution in the cavity a given amount. Therefore, as theconcentration of cleaning agent in the solution increases, the level towhich it is raised or held is lowered increasing amounts below the levelof the air opening and thus the volume of solution which flows from thecavity into the tank when the toilet is flushed (a volume equal to thevolume of solution above the bottom of the liquid opening) is decreased.This decrease is roughly in proportion to the increase in cleaning agentconcentration therein since the increase in concentration is reflectedin a proportional increase in specific gravity and corresponding drop inthe level of solution in the cavity. Thus, by proper selection of thedimensions of the dispenser and vertical distances between the air andliquid openings in relation to the particular solid cleaning agent beingused, the volume of solution dispensed upon each flush can be maintainedroughly inversely proportional to the cleaning agent concentrationtherein so that the cleaning agent output is maintained roughlyconstant.

In the preferred embodiments, the dispenser is formed from one or moresheets of flexible plastic, prepunched with suitably placed holes andappropriately rolled, pinched and sealed by automated machinery. Thedispenser can therefore be inexpensively produced with totally automatedmachinery and provide a uniform dispensing of cleaning agent,irrespective of the pattern of use.

BRIEF DESCRIPTION OF THE DRAWINGS

These and other aspects of the invention will be better understood fromthe following detailed description of the preferred embodiments whentaken with the accompanying drawings in which:

FIG. 1 is a saturation curve for a soluble cleaning material which maybe used in accordance with the present invention;

FIG. 2 is a schematic drawing of a dosing dispenser in accordance withthe present invention;

FIG. 3 is a perspective view of a dosing dispenser in accordance with apreferred structural embodiment of the invention;

FIG. 4 an elevational view of the dosing dispenser of FIG. 3;

FIG. 5 is a cross-sectional view taken along the lines 5--5 in FIG. 4;

FIG. 6 illustrates a prepunched sheet from which the embodimentillustrated in FIGS. 3-5 may be formed in accordance with one embodimentof a method of manufacture in accordance with the invention;

FIG. 7 is an elevational view of a second structural embodiment of theinvention;

FIG. 8 is an elevational view of a third structural embodiment of theinvention;

FIG. 9 is a cross-sectional view taken along lines 9--9 in FIG. 8;

FIG. 10 is an elevational view of a fourth structural embodiment of theinvention;

FIG. 11 is a cross sectional view taken along lines 11--11 in FIG. 10;and

FIG. 12 is a graph illustrating toilet tank and toilet bowl hypochloriteconcentration over the lifetime of a dispenser in accordance with thestructural embodiment illustrated in FIGS. 3-5.

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

Referring to FIG. 2, there is shown a schematic drawing of a dosingdispenser in accordance with the present invention. The dispenser 10includes an enclosure 11 having an internal cavity 12 for containing asolid, water soluble cleaning material 14 such as a cleaning agent. Theenclosure may be made from rigid walls, but in the preferred embodimenthas flexible walls 16.

Walls 16 are sealed along an upper edge 18, a lower edge 20, a rightside edge 22 and a left side edge 24. The left side edge 24 is providedwith a top or upper opening or hole 26, opening into the cavity 12 at anupper end of the edge 24, and a bottom opening 28, opening into thecavity 12 at a lower end of the edge 24. The openings 26 and 28 providethe only fluid communication between the cavity 12 and the exterior ofthe enclosure 11.

The dispenser may be suspended in a toilet tank as by a wire tie 30which may be inserted through a hole 32 in a sealed portion 34 of thedispenser above the top edge 18 of the enclosure 11.

The top opening 26 communicates with the exterior of the dispenserthrough an air inflow and outflow passage 36 which extends from the topopening 26 downward to a vent or vent opening 38. The bottom opening 28communicates with the exterior of the dispenser through a water inflowand solution outflow passage 40 extending upwardly from the bottomopening 28 to an inflow and outflow opening or orifice 42 located belowthe vent opening 38. Passages 36 and 40 may suitably be formed asportions of a continuous vertically extending channel 44 extendingcontinuously from the top opening 26 to the bottom opening 28 along theedge 24, with the vent opening 38 and inflow and outflow opening 42being formed in the channel 44.

In use, the dispenser is suspended in a toilet tank with the wire tie 30so that the quiescent water level designated by the reference numeral 46in FIG. 2, is above the vent opening 38. Tank water will automaticallyflow in the direction of arrow 48 into the inflow and outflow orifice42, through the passage 40 and into the cavity 12 through the bottomopening 28 to fill the cavity 12 up to the level 50. As the cavity 12 isbeing filled with tank water, excess air will be expelled through topopening 26, flow downward through passage 36 and bubble out of ventopening 38.

The initial water level 50 within the cavity 12 is aligned with the ventopening 38 since the pressure of the air trapped above the level 50 isequalized with the tank water at its interface therewith at the ventopening 38, and therefore, since the water on opposite sides of thebottom opening 28 has the same density, the water pressure on oppositesides of the bottom opening 28 are equal and thus the water inside andoutside the cavity 12 are in equilibrium and further flow into thecavity 12 ceases when the water level 50 is reached.

Thus, once the dispenser has been suspended in the toilet tank and thewater in the cavity 12 has reached an equilibrium level 50, air fillsthe air inflow and outflow passage 36 and water fills the water inflowand solution outflow passage 40 and fills the cavity 12 up to the level50 so as to submerge the block of cleaning material 14 therein andimmediately begins to dissolve the cleaning material to form a cleaningsolution in the cavity 12.

When the toilet is flushed, the tank water line drops below itsquiescent level 46, allowing the cleaning solution inside the cavity 12to flow through the bottom opening 28, up the water inflow and solutionoutflow passage 40 and into the tank through the inflow and outflowopening 42. However, the solution will continue to flow out of thedispenser only until its upper level drops to the level of the inflowand outflow opening 42. Thus, the solid block of soluble cleaningmaterial 14 will remain submerged in the solution inside cavity 12.

This inflow of tank water and outflow of solution each time the tankwater level drops and then rises when the toilet is flushed is repeatedwith each flush of the toilet.

As noted above, when the dispenser is freshly placed in the toilet tank,the distance, or cavity volume, between the vent opening 38 and theinflow and outflow opening 42 determines the amount of cleaning solutionwhich will be emitted from the dispenser each time the toilet isflushed. This dependency becomes somewhat more complicated as the blockof soluble cleaning material continues to dissolve into the solutionwithin the cavity 12 to increase the concentration of the dissolvedmaterial therein as explained below.

An appreciation of the effect of changing concentration of cleaningmaterial in the solution within the cavity 12 is perhaps best understoodby considering the passage 40 and the portion of the cavity 12 below thevent opening 38 as a "U" tube in which the head pressure of the tankwater in one side of the "U" balances the solution on the other side,and by considering the passage 36 and the portion of the cavity 12 abovethe vent opening 38 as an "inverted U" tube through which air isdisplaced from the cavity 12 as fresh tank water is added to raise thesolution level from the lower level 52 to the upper level 50.

Assuming that a block of calcium hypochlorite is utilized for thecleaning material, during the first few hours after placing a newdispenser in a toilet tank, the concentration of chlorine in solution inthe cavity 12 is very low, and the specific gravity of the solution andthe tank water is almost identical. Under these conditions, there isequal head pressure (weight) in both sides of the "U" tube and thecavity volume between the levels of the inflow and outflow opening 42and the vent opening 38 will completely refill with each flush of thetoilet. However, as time passes, and chlorine begins to saturate thesolution in the cavity 12, the specific gravity of the solutionincreases, and less solution in the cavity 12 is required to balance thetank water head pressure. Under these conditions, during a refill of thecavity 12, the tank water head pressure is not sufficient to completelypush the heavier cleaning solution in the cavity 12 to the level of thevent opening 38 before the tank water passes vent opening 38 and stopsflow into the cavity 12. This occurs because, as indicated above, whenthe level of the tank water is above the vent opening 38, air in the"inverted U" tube is compressed by and is at the same pressure as thetank water at the vent opening 38, this pressured air preventing furtherinflow of tank water via the "U" tube.

Referring now to FIGS. 3, 4, 5 and 6, a specific preferred embodiment ofthe dosing dispenser and of a method of manufacture thereof inaccordance with the present invention are illustrated. The dispenserbody in accordance with this embodiment is formed from a flexiblematerial, such a high-density polyethylene. The dispenser is formed froma rectangular sheet 100, illustrated in FIG. 6, having a top edge 102, abottom edge 104, and side edges 106 and 108. The sheet 100 is rolledinto a cylindrical shape such that the side edges 106 and 108 overlapand the now circular top and bottom edges 102 and 104 are pinched andsealed at right angles to each other so as to form a top sealed edge 110and a bottom sealed edge 112, bottom sealed edge 112 extendingperpendicularly to the top sealed edge 110 as shown in FIG. 3. Theportion 114 of the sheet 100 along the left side edge 106 overlaps theportion 116 of the sheet 100 along the right side edge 108 to theoutside thereof and is preformed to define a vertically extendingchannel 120 between the two overlapping portions 114 and 116, as bestshown in FIG. 5. Also, the holes in the sheet 100 are positioned in theside portions 114 and 116 so as to open into the channel 120. Inparticular, a triangularly shaped hole 122 is cut in the sheet portion114 so as to define a composite opening corresponding to the ventopening 38 and inflow and outflow opening 42 defined in schematicdrawing of FIG. 2, and holes 124 and 126 are formed in the sheet portion116 so as to respectively define a top opening and a bottom openingcorresponding to openings 26 and 28 illustrated in schematic drawingFIG. 2.

Referring to FIG. 4, it can be seen that the portion of the channel 120between the bottom edge of hole 122 and hole 126 forms a water inflowand solution outflow passage corresponding to passage 40 in schematicFIG. 2, and the portion of channel 120 between the upper edge of hole122 and the top hole 124 defines an air inflow and outflow passagecorresponding to passage 36 illustrated in schematic FIG. 2.

The overlapping parts of sheet portions 114 and 116 to either side ofchannel 120 are suitably heat sealed together.

Prior to heat sealing both of the top and bottom edges of the dispenser,a block of soluble cleaner material must be inserted in the centralportion of the dispenser defining the cavity 12. The inventor has isfound that if the diameter of the cavity 12 is 1.62 inches, the heightof the hole 122 is 9/16 inch, the distance from the sealed edge 112 tothe bottom of the hole 122 is 4 inches, the volume of the cavity belowthe hole 122 is 92 milliliters, and a 11/2 ounce block of calciumhypochlorite cleaning material is inserted in the cavity 12, then thedispenser will dispense sufficient calcium hypochlorite to the 11/2gallons of water in a standard toilet bowl during each of 350 flushes ofthe toilet over a 30 day period so that the concentration ofhypochlorite ions in the bowl water will consistantly be between 3 and41/2 parts per million over the 30 day period. This same test produced aconcentration of between 2 and 4 parts per million in the standard 41/2gallons of water in the toilet tank over the 30 day life of thedispenser. The results of this test are illustrated in FIG. 12 of thedrawings.

When the tested dispenser was first placed in the toilet tank, theinitial flushes resulted in a dispensing of 14 ml. of solutionrepresenting the volume of the cavity between the upper and lower edgesof the hole 122. However, after a few hours of operation, the outputvolume of solution from the cavity 12 decreased until ultimately, theoutput volume dropped to less than 2 ml. as the reservoir of solutionbecame fully saturated with the hypochlorite ions. As indicated above,this adjustment in the volume output automatically limits the totalchlorine output to a narrow range thereby maintaining the concentrationof ions in the tank and bowl to a similarly narrow range, as reflectedin the test results illustrated in FIG. 12.

In a dispenser to be sold commercially, it is important that the solidblock of cleaning material such as calcium hypochlorite be protectedfrom humidity during storage and prior to initial use. Accordingly, hole122 defining the vent opening 38 and inflow and outflow opening 42should be sealed as by a small stick-on tab which can be easily torn offprior to use, or the location of the hole 122 may be marked so that itmay be cut by the user just prior to the dispenser being inserted in thetoilet tank.

The inventor also found that although the water in the toilet tank is inconstant liquid communication with the interior of the cavity 12 andtherefore some hypochlorite ions will continuously migrate into the tankvia the passage 40, the total migration into the tank in this manner canbe kept insubstantial over the 30 day lifetime of the dispenser bysuitably limiting the cross-sectional area of the water inflow andsolution outflow passage 40. For example, such migration can be kept toa suitable minimum by limiting this cross-sectional area to about 0.15square inch.

Another embodiment of the dosing dispenser of the invention isillustrated in FIG. 7. This embodiment is substantially identical tothat of the prior embodiment except that the lower hole 126 is replacedby a plurality of inflow and outflow holes 130 whose size and spacingare defined to match the disbursing needs of the particular cleaningmaterial. This embodiment may be manufactured by the same method asdescribed above for manufacturing the prior embodiment. The inventor hasfound that a pattern of holes whose diameter increase in the downwarddirection along which they are aligned with decreasing distances betweenthe holes in the downward direction works well for several cleaningagent surfactants tested. With such a pattern, most of the flow in andout of the cavity 12 tends to be through the lower, larger diameter andmore closely spaced holes. This multiple hole approach worksparticularly well if the surfactant material is of a type whichdisintegrates and settles to the bottom of the cavity and therebytemporarily plugs up some of the bottom holes. In this condition, themajority of fresh water flowing into the dispenser unit tends to washthrough the lowest open hole, and thus, over (and mixing with) thesurfactant material directly under that hole. As the surfactant materialis depleted, lower output holes are progressively opened and the freshwater flow moves progressively lower in the unit to follow the decliningsurfactant level.

FIGS. 8 and 9 illustrate additional structural and method embodiments ofthe invention. These embodiments differ from the embodiments illustratedin FIGS. 3-6 primarily in that the cavity 12 is formed by heat sealingtogether front and rear sections 152 and 154 along fins or flanges 156and 158 respectively thereof. A U-shaped channel section 160 is heatsealed by flanges thereof onto the front section 154 so as to cover atop hole 162 and a bottom hole 164 vertically aligned in the frontsection 152, holes 162 and 164 respectively corresponding to the topopening 26 and the bottom opening 28 schematically illustrated in FIG.2. Channel section 160 has a vertically elongated hole 166 thereinvertically disposed between holes 162 and 164 so as to correspond to thevent opening 38 and inflow and outflow opening 42 schematicallyillustrated in FIG. 2. The composite structure of the dosing dispenserof this embodiment is similar in appearance and substantially identicalin operation to that of the previously described embodiment illustratedin FIGS. 3-5. This embodiment, however, is particularly suited formanufacture with horizontal fin seal production equipment.

FIGS. 10 and 11 illustrate a further structural embodiment of theinvention. This embodiment is similar to the embodiment illustrated inFIGS. 3-5 and differs therefrom only in that the channel which definesthe passageways between the bottom opening 28 and inflow and outflowopening 42, and between the top opening 26 and the vent opening 38 asschematically illustrated in FIG. 2, is formed in the inside lappedportion 182 rather than in the outside lapped portion 114 as in theembodiment of FIGS. 3-5. Thus, the inside lapped portion 182 is formedto project inward of the cavity 12. This embodiment also differs fromthe embodiment of FIGS. 3-5 in that the vent opening and inflow andoutflow opening are formed by separately and spaced apart holes 184 and186 in the outer lapped portion 188 opposing the channel 180. As withthe embodiment of FIGS. 3 and 5, the dispenser is formed from a singlerectangular sheet having holes preformed therein similarly to that shownin FIG. 6, and the sheet is suitably formed and sealed to produce thestructure illustrated in FIGS. 10 and 11 in a manner similar to thatdescribed above for the manufacture of the embodiment of FIGS. 3-5.

While particular embodiments of the invention have been illustrated anddescribed, it will be obvious to those skilled in the art that variouschanges and modifications can be made without departing from the spiritand scope of the invention. The appended claims are intended to coverall such embodiments within the scope of the invention. For example,while the dispensers in accordance with the preferred embodiments of theinvention are formed from a flexible sheet material, the dispenserscould also suitably be formed from rigid members in which the requiredcavity and flow passages are molded or otherwise so formed as to achievethe self-regulated output taught by the invention.

What is claimed is:
 1. A dosing dispenser for immersion in a body ofwater whose level can be raised and lowered between an upper level and alower level, comprising:an enclosure having an internal cavity forcontaining a solid, water soluble material, said enclosure having aclosed sealed bottom, a closed sealed top above said bottom, and sidewalls extending upward from said bottom to said top, enclosing saidcavity; means, including a water inflow and solution outflow passagehaving at respective ends thereof a first opening opening into saidcavity through said side walls at a first vertical level below said top,and a second opening opening exteriorly of the dispenser at a secondvertical level below said top and above said first opening, for guidingwater from the body of water into said cavity through said first andsecond openings when the level of the body of water rises from the lowerlevel to the upper level and for guiding solution from the enclosureinto the body of water when the level of the body of water falls fromthe upper level to the lower level, when the dispenser is disposed inthe body of water such that the upper level is above said second openingand the lower level is below said second opening; and means, includingan air inflow and outflow passage having at respective ends thereof athird opening opening exteriorly of said dispenser at a third verticallevel below said top and above said second opening, and a fourth openingopening into said cavity through said side walls at a fourth verticallevel above said third opening, for guiding air from the exterior of thedispenser into said cavity through said third and fourth openings whenthe level of the body of water falls from the upper level to the lowerlevel, and for guiding air from the cavity to the exterior of thedispenser when the level of the body of water rises from the lower levelto the upper level, when the dispenser is disposed in the body of watersuoh that the upper level is above said second opening and the lowerlevel is below said second opening; said side walls being sealed againstfluid flow between said cavity and the exterior of the dispenser throughthe portion of said side walls between said second level and said fourthlevel and through the portion of said side walls between said fourthlevel and said top.
 2. A dosing dispenser as in claim 1, furthercomprising a quantity of solid, water soluble sanitizer material in saidcavity.
 3. A dosing dispenser as in claim 2, wherein said side walls,said top, said bottom, said air inflow and outflow passage and saidwater inflow and sollution outflow passage are formed of a singleflexible sheet having first, second, third and fourth holes thereinrespectively defining the first, second, third and fourth openings, saidsheet having a top edge, a bottom edge and opposite first and secondside edgs connecting opposite ends of said top and bottom edges, saidtop edge being folded over itself and sealed so as to extend in a firsthorizontal direction and form said closed sealed top, said bottom edgebeing folded over itself and sealed so as to extend in a secondhorizontal direction perpendicular to said first horizontal directionand form said closed sealed bottom, said first side edge and said secondside edge respectively ovelapping said second side edge and said firstside edge and respectively sealed to respective sealed surface areas ofthe sheet spaced from and adjacent to said second side edge and saidfirst side edge so as to define a channel between opposing first andsecond exposed overlapping surface areas of said sheet respectivelybetween between said first side edge and said first sealed surface area,and said second side edge and said second sealed surface area, saidfirst edge being disposed inside said second edge, said first and fourthopenings being formed in said first exposed surface area, said secondand third openings being formed in said second exposed surface area, sothat the portion of said channel between said first and second openingsdefines said water inflow and solution outflow passage and the portionof said channel between said third and fourth openings defines said airinflow and outflow passage.
 4. A dosing dispenser as in claim 3, whereinsaid second and third openings share a common edge therebetween anddefine a common vertically elongated hole extending from said secondvertical level to said third vertical level.
 5. A dosing dispenser as inclaim 1, wherein said enclosure has said first and fourth openingsformed therein in vertical alignment, said means for guiding air andsaid means for guiding water and guiding solution comprising a channelmember fixed to said enclosure and covering said first and fourthopenings and defining a channel between said enclosure and said channelmember communicating with said first and fourth openings, said channelmember having said second and third openings therein so that the portionof said channel between said first and second openings defines saidwater inflow and solution outflow passage and the portion of saidchannel between said third and fourth openings defines said air inflowand outflow passage.
 6. A dosing dispenser for immersion in a body ofwater whose level can be raised and lowered between an upper level and alower level, comprising:an enclosure having an internal cavity forcontaining a quantity of water and a quantity of a solid, water solublematerial of a type which, when dissolved in water, increases thespecific gravity of the resulting solution in proportion to theconcentration of the material in the solution; means for fixing saidenclosure in a body of water at a predetermined position with respect toan upper level thereof; and means, connected to said enclosure andresponsive to at least one of lowering and raising of the level of thebody of water between the upper and lower level, for dispensing to thebody of water a dose of a solution of water and a quantity of the watersoluble material dissolved therein from said cavity, and drawing aquantity of water from the body of water into said cavity, when saidenclosure is fixed in the body of water by said fixing means with thequantity of water soluble material contained in said cavity, saiddispensing and drawing means including volume decreasing means fordecreasing the volume of the dose in proportion to the concentration ofthe water soluble material dissolved therein.
 7. A dosing dispenser asin claim 6, wherein said varying means includes level lowering means forlowering the level of a solution in the cavity when the body of water isat the upper level in proportion to the concentration of water solublematerial dissolved therein and means for controlling the volume of thedose in proportion to the level of the solution.
 8. A dosing dispenseras in claim 7, wherein said cavity has an upper end portion in thecavity, said level lowering means including means for sealing the volumeof said upper end portion so as to trap air in said upper end portionunder pressure to thereby limit the upward movement of the level of thesolution in the cavity while water is being drawn into said cavity bysaid dispensing and drawing means.
 9. A dosing dispenser for immersionin a body of water whose level can be raised and lowered between anupper level and a lower level, comprising:an enclosure having aninternal cavity for containing a solid, water soluble material, saidenclosure having a closed sealed bottom, a closed sealed top above saidbottom, and side walls extending upward from said bottom to said top,enclosing said cavity; means, including a water inflow and solutionoutflow passage having at respective ends thereof a first opening meansopening into said cavity through said side walls at a first verticallevel below said top, and a second opening means opening exteriorly ofthe dispenser at a second vertical level below said top and above saidfirst opening means, for guiding water from the body of water into saidcavity through said first and second opening means when the level of thebody of water rises from the lower level to the upper level and forguiding solution from the enclosure into the body of water when thelevel of the body of water falls from the upper level to the lowerlevel, when the dispenser is disposed in the body of water such that theupper level is above said second opening means and the lower level isbelow said second opening means; and means, including an air inflow andoutflow passage having at respective ends thereof a third opening meansopening exteriorly of said dispenser at a third vertical level belowsaid top and above said second opening means, and a fourth opening meansopening into said cavity through said side walls at a fourth verticallevel above said third opening means, for guiding air from the exteriorof the dispenser into said cavity through said third and fourth openingmeans when the level of the body of water falls from the upper level tothe lower level, and for guiding air from the cavity to the exterior ofthe dispenser when the level of the body of water rises from the lowerlevel to the upper level, when the dispener is disposed in the body ofwater such that the upper level is above said second opening means andthe lower level is below said second opening means; said side wallsbeing sealed against fluid flow between said cavity and the exterior ofthe dispenser through the portion of said side walls between said secondlevel and said fourth level and through the portion of said side wallsbetween said fourth level and said top; said enclosure having said firstand fourth opening means formed therein in vertical alignment, saidmeans for guiding air and said means for guiding water and guidingsolution comprising a channel member fixed to said enclosure andcovering said first and fourth opening means and defining a channelbetween said enclosure and said channel member commmunicating with saidfirst and fourth opening means, said channel member having said secondand third opening means therein so that the portion of said channelbetween said first and second opening means defines said water inflowand solution outflow passage and the portion of said channel betweensaid third and fourth opening means defines said air inflow and outflowpassage, said first opening means including a plurality of spaced,vertically aligned holes in said enclosure.
 10. A dosing dispenser as inclaim 9, wherein said holes are of successively decreasingcross-sectional area in an upward direction.
 11. A dosing dispenser forimmersion in a body of water whose level can be raised and loweredbetween an upper level and a lower level, comprising:an enclosure havingan interval cavity for containing a solid, water soluble material, saidenclosure having a bottom, a top above said bottom, and side wallsextending upward from said bottom to said top, enclosing said cavity;means, including a water inflow and solution outflow passage having atrespective ends thereof a first opening opening into said cavity at afirst vertical level below said top, and a second opening openingexteriorly of the dispenser at a second vertical level below said topand above said first opening, for guiding water from the body of waterinto said cavity through said first and second openings when the levelof the body of water rises from the lower level to the upper level andfor guiding solution from the enclosure into the body of water when thelevel of the body of water falls from the upper level to the lowerlevel, when the dispenser is disposed in the body of water such that theupper level is above said second opening and the lower level is belowsaid second opening and the lower level is below said second opening;and means, including an air inflow and outflow passage having atrespective ends thereof a third opening opening exteriorly of saiddispenser at a third vertical level below said top and above said secondopening, and a fourth opening opening into said cavity at a fourthvertical level above said third opening, for guiding air from theexterior of the dispenser into said cavity through said third and fourthopenings when the level of the body of water falls from the upper levelto the lower lever, and for guiding air from the cavity to the exteriorof the dispenser when the level of the body of water rises from thelower level to the upper level, when the dispenser is disposed in thebody of water such that the upper level is above said second opening andthe lower level is below said second opening; said side walls, said topand said bottom comprising means for sealing said cavity against fluidflow between said cavity and the exterior of said enclosure exceptthrough said first and second openings via said water inflow andsolution outflow passage and through said third and fourth openings viasaid air inflow and outflow passage.